This invention relates to strip inlay products which are mounted in shallow elongate channels in generally continuous substrates. Typical substrates are wood, but such inlays can also be used with plastic metal, and other substrates. Inlay products are used to add decorative features to a wide variety of products, including stringed instruments, furniture, flooring, walls, and the like. Inlay products can also be used to decorate a wide variety of consumer products including electronics.
The invention is described in detail herein with respect to implementations in stringed instruments, with the understanding that the same principles can be used in applying the invention to other products such as, without limitation, those mentioned above.
The substrates in e.g. stringed musical instruments are typically quite thin, such as no more than 0.10 inch thick. The depth of the channel is sufficiently shallow to not penetrate the entirety of the thickness of the substrate. At the same time, the thickness of the substrate may be driven by considerations other than the strip inlay product. For example, in stringed musical instruments, the thickness of the substrate may be driven by the influence of the substrate thickness on tonal or other characteristic of the music produced by the instrument. In addition, the inlay product, itself, may have some affect on the characteristic of the music produced by the instrument.
Thus, the dimensions of the inlay product may be somewhat guided by the requirements of the instrument or other substrate while also being somewhat guided by the appearance benefits of the inlay product. Namely, the thickness of the inlay product must be thin enough to be received within the thickness of the substrate, and the width and length of the inlay product must be great enough to have the desired pleasing appearance affect.
The use of conventional strip inlay products has historically been limited by the nature of the decorative inlay products which are available. In general, such strip inlay products are made by                (i) fabricating one or more, optionally several, inlay precursor wood laminates of differing wood species composition, typically differing by color, at respective locations in the laminate, and/or including vulcanized fiber substrate,        (ii) slicing thin sheets from the respective wood laminates, across the laminate structure, so as to expose end grain surfaces of the wood and thereby capture, in each such sheet, the color variation represented by the various wood species end grains in the respective laminate, and        (iii) optionally, gluing multiple ones of such sliced sheets together to make an inlay product having a mosaic or like pattern.        
Thus, the conventional method of fabricating high quality purfling inlay products is a form of marquetry, wherein the structure of any portion of the display surface of the inlay extends from the visible displayed top surface of the inlay product through the entirety of the thickness of the inlay product, to the bottom surface of the inlay.
Such conventional wood inlay products are typically fabricated using e.g. vulcanized fiber substrate and/or a variety of species of wood to create a pleasing color arrangement in the finished inlay product.
Such inlay products are typically fabricated and marketed as straight-line strip inlay products. Where such straight-line strip inlay products are to be inlayed into a channel, such as along the curved edge of the box of a stringed instrument, for example in a guitar, the inlay product is known as purfling. Where such straight-line strip inlay product is to be inlayed into a channel away from the curved edge of the sound box, the inlay product is known as an inlay strip.
Where the channel into which the straight-line strip inlay product is to be mounted is curved, the strip inlay product must be flexed into the shape of the channel curves in order to fit into the curved channel. But the wood in the strip inlay product makes the strip inlay product quite rigid and resistant to flexing. It is not uncommon for the wood assembly of the straight-line strip inlay product to be broken while being flexed. Recognizing the need for such flexing, the manufacturers of such wood strip inlay product suggest heating the product to soften the product in order to facilitate such flexing. While heating provides some improvement in the ability to flex the straight-line strip inlay product, the industry still experiences substantial loss due to breakage of such wood inlay products during the attempted flexing step.
It is also known to apply humidity and/or other moisture to the strip inlay product in order to soften the wood and thus further facilitate the flexing/bending step. However, in spite of the use of such procedures to avoid breakage, the industry still experiences a substantial amount of breakage of such wood strip inlay products during the process of flexing/bending the product in preparation for, or in the process of, installing the strip inlay product into a curved channel. Some users flex/bend the strip inlay product in the process of installing the strip inlay product into the channel, whereby the breakage occurs at or proximate the channel such that a length of a strip which has been broken, but where the pieces have not separated substantially from each other, can be inserted into the channel with limited visible evidence of the break. Such breakage may be subsequently concealed or camouflaged by fillers, sawdust, or the like during the process of providing the overall surface finish on the resulting e.g. instrument of other product by sanding, filling, varnishing, and the like.
Given that purfling may be provided as a value-added feature in such products, there is an accompanying expectation that the value-added feature will be perceived by the customer as providing a higher quality product. Thus, the quality of the inlay strip is desirably as high as possible, and breakage, even where skillfully concealed or camouflaged, is not perceived as providing a high quality product.
While there is substantial use of such wood purfling strips in curved channels, the industry continues to struggle with breakage of the purfling strips in such applications. In any event, uses of curved purfling inlay products are limited to purfling inlay products having visualizable widths, after installation, of no greater than about ⅛ inch. While purfling strips of greater widths are available, and are desirable for the benefits of the enhanced visualization surface area, such greater-width purflings cannot be bent to any significant degree about an axis perpendicular to the top of the inlay, and are thus not used in curved channels in a flat plate such as the top or bottom plate.
As an alternative to straight strips of wood purfling, it is known to cut curved purfling strips from a wood substrate using e.g. a laser cutter. But each such curved purfling strip has a given curvature pattern which is designed/adapted for use only in a channel having the same curvature pattern. Thus, in fabricating curved wood purfling strips for the curved outer perimeter of the top plate of a guitar box, a separate curved purfling inlay strip is engineered and created for each length increment along the perimeter of the guitar. Accordingly, much hand labor and skill is required in designing and creating each such length of curved purfling inlay product.
As an alternative to wood purfling, it is known, as in U.S. Pat. No. 5,776,581 Sifel et al, to cut thin pieces of shell material from organic e.g. seashells, to laminate such pieces to each other to make laminated sheets, and to reduce the thickness of such laminated sheets to a thin dimension which is compatible with a limited degree of flexing of the laminated sheet structure about an axis which is perpendicular to a side edge of the strip but not about an axis which is perpendicular to the top of the strip product. Thin decorative strips are cut from the laminated sheet material. The resulting strips exhibit no useful flexibility.
The purpose of such shell inlay strips is typically to present a substantial size surface of the resultant strip for visualization on the surface of the instrument.
While the resulting shell inlay strips can, to a limited extent, be flexed in the first direction, namely the thinner dimension of the resultant strip, in order for the decorative purpose of the strip to be provided, the relatively larger surface of the strip is desirably presented for visualization in the top plate of the instrument sound box. And such larger surface can be presented for visualization by forcing the strip into the channel with the larger surface of the strip facing outwardly, allowing the strip to fracture/break in the process of inserting the strip into the channel, confining as possible, the broken ends so as to keep the ends in close contact with each other, and then concealing the broken ends of the strip during the process of finishing the outer (e.g. top) surface of the instrument. This process succeeds to an extent so long as the ends can be kept close to each other and closely lined up with each other. However, where breakage is accompanied by shell material completely separating from the strip, the resulting ends may not closely line up with each other, resulting in a further visual defect in the product.
As yet another option, curved strips or other non-straight-line-shaped product may be cut from the laminated shell sheet, where the curvature/shape of each piece is configured to fit into a correspondingly configured channel in the substrate to which the strip is to be mounted.
Examples of currently available purfling products are shown in Catalog 1010 of Luthier's Mercantile International, Inc., Windsor, Calif.
It would be desirable to provide a strip inlay product which can be flexed at will into whatever curved shape is expressed by the sound box without compromising the integrity of the purfling structure.
In light of the substantial amount of detailed hand labor involved in making conventional strip inlay product structures, it would also be desirable to provide more cost effective methods of making strip inlay product structures, such that such strip inlay product structures can be produced by automated methods.
It would be further desirable to provide cost effective methods of making flexible strip purfling structures wherein the strip purfling structure can be readily and reliably bent/flexed about an axis perpendicular to a side edge of the strip, to fit into curved receptacle channels following the curved outer perimeter of otherwise-conventional sound boxes of stringed instruments.
It would be still further desirable to provide straight-line inlay strip products wider than ⅛ inch, e.g. up to about 0.3 inch or more, which can be readily and reliably bent/flexed to fit into curved receptacle channels.
It would also be desirable to provide strip inlay products, such as purfling products, which have design options beyond those offered by marquetry laminations such as words and other designs not readily made by marquetry or other lamination techniques.
It would be still further desirable to provide methods of fabricating strip inlay products, such as purfling products, which provide additional design options, beyond marquetry, which use lesser amounts of hand labor, and which avoid certain assembly problems.
In addition to thin strip inlay products, it is also known to inlay a rosette or other decorative border, which is typically greater than 0.25 inch wide and up to about 1 inch wide, about the sound aperture(s) in a stringed instrument. For example, circular rosette rings are known to be inlayed about the sound aperture of a guitar.
A relatively simple circular rosette ring inlay product is a thin veneer of wood, cut in a pattern whose inner perimeter reflects the perimeter of the sound aperture about which the rosette is to be mounted.
More complex rosettes are fabricated, again by marquetry, from wood, using laminates which display the end grain of the wood laminates, similar to the laminates used in wood strip purfling inlay products. In fabricating a series of rosettes, first a series of laminates are made, and adhered to each other edge to edge to fabricate an elongate log representation of the circular or other shape of the desired rosettes. Very short lengths of the edge-adhered laminates are cut from the elongate log structure so as to express the end grain of the wood across the cut surface, thus making multiple rosette products, each expressing the same visualization pattern, from each such rosette log.
In the alternative, the elongate log may represent only a portion of the circular ring shape, and the pieces cut from the log are subsequently assembled to each other, edge to edge, in fabricating the rosette.
As with strip purfling inlay products, the fabrication of a rosette-type inlay product uses substantial hand labor in the assembly of the various laminate strips to each other, as well as in the assembly of the log. As with purfling strip inlay products, a channel is cut in the top plate of the instrument, namely about the perimeter of the sound aperture, and the rosette product is in-laid into the channel.
Thus, it would be desirable to provide rosette inlay products which can be fabricated using limited hand labor.
It would be further desirable to provide rosette inlay products which have design options beyond those offered by marquetry laminations.
It would be still further desirable to provide methods of fabricating rosette inlay products which provide additional design options, which use lesser amounts of hand labor, and which avoid certain assembly problems.
These and other needs are alleviated, or at least attenuated, by the novel products and methods of the invention.